Assessing the activity of perianal Crohn's disease: comparison of clinical indices and computer-assisted anal ultrasound.

Adult, Aged, Anus Diseases; ultrasonography, Crohn Disease; ultrasonography, Evaluation Studies as Topic, Female, Humans, Image Interpretation; Computer-Assisted, Male, Middle Aged, Rectal Fistula; ultrasonography, Sensitivity and Specificity, United States, United States Food and Drug Administration